The present invention comprises a new and distinct cultivar of calla lily, botanically known as Zantedeschia sprengeri and hereinafter referred to by the cultivar name ‘Summer Sun’.
‘Summer Sun’ is a product of a planned breeding program which had the objective of creating Zantedeschia hybrids for pot flower production in a wide range of colors with a large, classic flower shape. The breeding program began in 1989, and the new cultivar is a seedling selected from the crossing of Zantedeschia sprengeri ‘Red Sox’ (female parent, U.S. Plant Pat. No. 14,063) with Zantedeschia sprengeri ‘Sunglow’ (male parent, unpatented). ‘Summer Sun’ was selected in 2004 by the inventor in 't Zand, The Netherlands as one flowering plant within the progeny of the stated cross.
The first act of asexual reproduction of ‘Summer Sun’ by tissue culture was performed by the inventor in September of 2007 in 't Zand, The Netherlands. Subsequent asexual reproductions by tissue culture at the same location have demonstrated that the combination of characteristics as herein disclosed for the new cultivar are retained and reproduced true to type through successive generations of asexual reproduction.
The following observations, measurements and comparisons describe plants grown in a 14 cm pot at 12-14 weeks after planting in 't Zand, The Netherlands under greenhouse conditions, which approximate those generally used in horticultural practice. Color references are made to The 2001 R.H.S. Colour Chart of The Royal Horticultural Society of London, except where general color terms of ordinary significance are used.
The present invention has not been evaluated under all possible environmental conditions. The phenotype may vary with variations in environment without a change in the genotype of the plant.
The following traits have been repeatedly observed and determined to be basic characteristics of ‘Summer Sun’ which, in combination, distinguish this calla lily as a new and distinct cultivar:                1. Yellow-colored spathe having a pink blush;        2. Green-colored leaves with numerous white-colored and linear spots; and        3. High inflorescence production.        
Further, when compared to calla lily plant named ‘Yellow Jacket BLZ’ (U.S. Plant Pat. No. 20,217, the upper surface spathe color of ‘Yellow Jacket BLZ’ is Yellow Group RHS 7A and the lower surface spathe color of ‘Yellow Jacket BLZ’ is Yellow Group RHS 7B, whereas the upper and lower surface spathe color of ‘Summer Sun’ varies between Yellow Group RHS 9A to 9B.
Table 1 provides similarities and differences of ‘Summer Sun’ to its parents, Zantedeschia sprengeri varieties ‘Red Sox’ and ‘Sunglow’.
TABLE 1‘Summer Sun’SimilaritiesDifferences‘Red Sox’Plant heightSpathe color (Varies betweenGreyed-Purple Group RHS182A to 184A)Number of inflorescences (1-4)Spathe shape (Between funneland cupped)‘Sunglow’Number ofSpathe shape (Funnel)inflorescencesPlant height (10-30 cm)Spathe color (Reddish-orange incolor, RHS values unknown)